At roughly 3 p.m. Monday, Ntshanga was checking his e-mail at the computer terminal outside the Greenhouse Cafe when Gonzalez asked him to take his bike out of the Science Center.

He did not remove the bike immediately; Gonzalez returned after roughly five minutes and told Ntshanga to get out of the building when he could not produce his student ID.

Ntshanga said he understood the guard's concern and quickly locked his bike outside the building.

"I didn't get upset because I asked him too many questions," he said.

After locking his bike, Ntshanga re-entered the Science Center. He quickly found a basement computer where he could continue the e-mail message he had postponed.

Gonzalez followed Ntshanga downstairs and asked to see his student ID once again.

Ntshanga explained that he did not have the identification. Instead, he presented his bank card and asked for the guard's name.

Gonzalez refused to give his name and called police. Johnson said the guard violated policy by refusing to give his name.

While Gonzalez was calling for police assistance, Ntshanga, who lives off-campus, called his senior tutor, Mary Peckham of Mather House. Ntshanga said he hoped Peckham could help identify him as a student.

But Peckham's assistance was not needed. Officer Phillip Murphy and three other Harvard police who came to the scene allowed Ntshanga to leave.

Dean of Students Archie C. Epps III said he thinks guards and police officers should try to identify students without blowing a situation out of proportion.

"I would prefer police to use alternate methods of identifying people if at all possible," said Epps, who criticized the police for their handling of Ntshanga's 1992 arrest.

Monday's incident rekindled memories of his 1992 arrest, Ntshanga said.

"I've gone to jail for something exactly like this," he said. "I'm the one who is supposed to throw everything behind and forget."

Ntshanga met with Vice President General Counsel Margaret H. Marshall on September 9 to discuss the 1992 arrest.